It can be shown that the passage of ultrasonic waves through a tissue medium causes a previously unreported periodic modulation of the tissue resistance. If bioelectric currents are flowing in the sound path, amplitude modulation of the currents at the sound frequency rate have been observed. Using this effect, it may be possible to develop a type of noninvasive bioelectric current imaging modality which could be potentially very useful in medical diagnostics and electrophysiological research. This basic approach would in principle show physiologic function through visualization of biochemical electron exchange and ion transport phenomena rather than physical structure. This research proposes to examine the feasibility of developing such an instrument and identify the factors important in its operation. This will be accomplished through the use of tissue and gel models with artificially introduced ionic current flows. Measurement of acoustic wave interactions with the currents will be by surface biopotential electrodes and signal processing applied to extract location specific information concerning bioelectric current flows.